Gaseous electric discharge apparatus



Feb. 10,1942; M AgEDwARns 4 2,272,770

- GASEOUS ELECTRIC DISCHARGE APPARATUS Fi led Oct. 24, 1959 Inventor Martin A. Edwards, 9

His Abtorney.

Patented Feb. 10, 1942 FICE Gaseous anaemic nrsonsnon arrm'rns Martin A. Edwards, Schenectady, N. 1, minorto General Electric Company, a corporation of New York Application octane: 24, 1939,. Serial No. 300,991

6 Claims. (01. 176-124) My invention relates to gaseous electric discharge devices, such as discharge lamps, and apparatus for operating them from alternating current circuits. It relates particularly to discharge devices which have electrodes that are initially heated to an electron emitting temperature and to apparatus which, when the electrodes have reached that temperature, applies the starting voltage to the device. It is the object of my invention to provide apparatus of this character having improved means for determining th time delay during which the electrodes are heated and before which the starting voltage is applied across the device. A further ob- Ject of my invention is the provision of apparatus of this character which is quiet, which provides accurate timing, which automatically corrects for changes in the ambient temperature, and which is inexpensive to manufacture.

My invention will be better understood from the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

In the single figure of the drawing which is a circuit diagram illustrating an embodiment of my invention, 1 represents an electric discharge device or lamp having an electrode 2 at either end thereof which electrodes are repre-- sented as of filamentary form. The electrodes connect at one end through the connections 3 and 4 with the source of alternating current supply 5 which for example may be a 115 volt, 60 cycle lighting circuit. These connections include the switch 6, the ballast reactor 7 and the reached, the potential difference across the resistor I is insuiiiclent to cause the switch It) to be opened. However, by the time that the electrodes have reached the proper temperature for the application of the starting voltage, the potential difference across the resistor will have risen to such a'point that the pull of the winding H is able to overcome thebias of the switch. The inductive kick. due to the opening of the heating circuit by the switch then-starts the discharge across the device. From then on the current taken by the device in passing through the resistor. produces a sufiicient voltage drop therethrough to maintain the switch in open circuit position. In the event of a'momentary failure of the source of supply the switch may close but upon a re-establishment of the line voltage, the switch ,willbe opened as before which may require less time if the electrodes and the resistorare still hot. By constructing a resistor similar to the electrodes of the device, it automatically corrects for changes in ambient temperature. 'Ihe apparatus also works quietly and provides for accurate timing of the electrode heating interval before the application of the starting voltage.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. An electric discharge device having elec-- trodes adapted to be initially heated to an electron emitting temperature, means including a I thereof and means responsive to an increase in the potential difference across said resistor due to the heating thereof by the current therein with the winding u by which it is moved to its open circuit position. The winding H is supplied with rectified current obtained from the full wave rectifier l2 which is connected across the resistor a whereby the winding is responsive to the potential difference across the resistor.

When the switch 8 is closed to energize the device, there is a relatively large current flow through the resistor 8, the electrodes of the device and the switch I0 which current quickly brings the electrodes 2 to an electron emitting for interrupting the heating current between said electrodes.

2. An electric discharge device having electrodes adapted to be initially heated to an electrom emitting temperature, means including a resistor for connecting said device with a source of alternating current supply and providing a current path including said electrodes for the initial heating thereof,'a switch in said current path between said electrodes and means responsive to an increase -in the potential difference across'said resistor due to the heating thereof by the current therein for opening said switch.

3. An'eiectric discharge device having electrodes adapted to be. initially heated to an electron emitting temperature, means including a resistor of acharacter similar to that of said temperature. Until this temperature has been as electrodes for connecting theelectrodes of said device with a source of alternating current supply, a switch connecting said electrodes to complete a heating circuit therethrough and means for opening said switch in response to a predetermined increase in the potential difference across said resistor due to the heating thereof a by the current therein.

4. In combination, a source of alternating current supply, an electric discharge device having electrodes adapted to be initially heated to an electron emitting temperature, connections between one end of each of said electrodes and said source, a switch connecting the other ends of said electrodes, a resistor having a positive resistance-temperature coefllcient in one of said connections and electromagnetic means responsive to the rise in potential diiTerence across said resistor resulting from the flow of current therethrough for opening said switch.

5. In combination, a source. of alternating current supply, an electric discharge device having electrodes adapted to be initially heated to an electron emitting temperature, connections between one end of each of said electrodes and plying energy from a source of alternating our rent to said device during the normal operation thereof, a resistor having a positive resistancetemperature coemcient in one of said connections, a circuit connected between said electrodes for conducting heating current therefor and a switch arranged to open said circuit in response to a predetermined increase in the potential diiference across said resistor due to the passage of said heating current therethrough.

- MARTIN A. EDWARDS. 

